UPDATE 1-Durect's partner Pfizer to end pain drug deal

March 1 (Reuters) - Specialty pharmaceutical company Durect Corp said its partner Pfizer Inc will terminate their agreement for the development and commercialization of a patch to treat chronic low-back pain.

The patch failed to meet the main goal of a mid-stage trial in April 2011.

Pfizer acquired the rights of the drug, Eladur, through its acquisition of King Pharmaceuticals, which in turn had bought Alpharma Ireland Ltd. In 2008, Alpharma paid Durect an upfront payment of $20 million for Eladur.

Durect shares closed at 72 cents on Thursday on the Nasdaq.